GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 1999 🢒 Regal 🢒 Body and Accessories 🢒 Body Control System 🢒 DTC B2533 Foglamp Switch Circuit Shorted to B+

Object Number: 385150 Size: LF

Circuit Description

When the ignition switch is on, the BCM provides a ground feed to the fog lamp switch through circuit 192. Turning the fog lamp switch to the ON position sends a ground signal from circuit 192 to circuit 1317, enabling the FOG LP relay.

Conditions for Setting the DTC
    • The BCM detects a short to B+ in circuit 192 when the ignition switch is on.
    • The BCM detects a short to B+ in circuit 1317 when the ignition switch is on and the fog lamp switch is on.

Action Taken When the DTC Sets
    • The BCM stores DTC B2533 in memory.
    • The BCM turns off its output to the fog lamp relay.

Conditions for Clearing the DTC
    • Voltage is no longer detected by the BCM in circuit 192 when the ignition switch is cycled from off to on.
    • A history DTC will clear after 100 consecutive ignition cycles if the condition for the fault is no longer present.
    • An ignition cycle is needed to change the status of this DTC from current to history.
    • Using a scan tool.

Diagnostic Aids
    • The following conditions may cause an intermittent malfunction to occur:
       - An intermittent short to B+ in circuit 192.
       - An intermittent short to B+ in circuit 1317.
    • If the DTC is a history DTC, the problem may be intermittent. Try performing the tests shown while moving wiring and connectors, this can often cause the malfunction to reappear.
    • DTC P1626 will set in the Powertrain Control Module (PCM) when the ignition switch is on with the Body Control module (BCM) disconnected. When BCM diagnostics and repairs are completed, refer to Engine Controls for additional information on PCM related DTCs.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. This step checks for a short to B+ in circuit 192.

    2.

  2. This step determines whether circuit 192 has a short to B+ or the BCM is faulty.

    3.

  3. This step checks for a short to B+ in circuit 1317.

    4.

  4. This step determines whether circuit 1317 has a short to B+ or the FOG LP relay is faulty.

    5.

  5. This step checks for a short to B+ in the fog lamp switch.

    6.

  6. This step determines whether the short to B+ is in the underhood accessory wiring junction block or in circuit 1317.

Step

Action

Value(s)

Yes

No

1

Was the BCM Diagnostic System Check performed?

--

Go to Step 2

Go to Diagnostic System Check - Body Control System

2

  1. Turn the ignition switch off.
  2. Disconnect the fog lamp switch.
  3. Turn the ignition switch on.
  4. Using a DMM, measure the voltage between the fog lamp switch harness connector terminal D and ground.

Is the voltage measured within the specified range?

Less than 2V

Go to Step 4

Go to Step 3

3

  1. Leave the DMM connected form the previous step.
  2. Turn the ignition switch off.
  3. Disconnect the Body Control Module (BCM) connector C1.
  4. Turn the ignition switch on.
  5. Using a DMM, measure the voltage again.

Is the voltage measured within the specified range?

Less than 2V

Go to Step 8

Go to Step 9

4

  1. Turn the headlamps switch to the HEAD position.
  2. Turn on the headlamp high beams.
  3. Using a test light, backprobe between the fog lamp switch connector terminal E and ground.

Is the test light on?

--

Go to Step 5

Go to Step 6

5

  1. Leave the test light in the same location from the previous step.
  2. Disconnect the FOG LP relay.

Is the test light on?

--

Go to Step 7

Go to Step 11

6

  1. Turn the ignition switch off.
  2. Reinstall connectors/components removed.
  3. Turn the ignition switch on.
  4. Using a test light, connect by backprobing between the fog lamp switch connector terminal D and ground.

Is the test light on?

--

Go to Step 12

Go to Step 8

7

  1. Leave the test light in the same location from the previous step.
  2. Turn the ignition switch off.
  3. Disconnect the underhood accessory wiring junction block connector C2.
  4. Turn the ignition switch on.

Is the test light on?

--

Go to Step 13

Go to Step 14

8
  1. Turn the ignition switch off.
  2. Reinstall connectors/components removed.
  3. Turn off the headlamps.
  4. Turn the ignition switch on.
  5. Clear BCM DTCs. Refer to Clearing DTCs for more information.
  6. Activate the fog lights.
  7. Check for BCM DTCs. Refer to Diagnostic Trouble Code (DTC) Displaying for more information.

Does BCM DTC B2533 reset as a current DTC?

--

Go to Step 10

Go to Step 15

9

Repair a short to B+ in circuit 192 between the fog lamp switch connector terminal D and the BCM connector C1 terminal C8.

Is the repair complete?

--

Go to Step 16

--

10
  1. Replace the BCM. Refer to Body Control Module Replacement for more information.
  2. After replacing the BCM, perform the Setup New BCM procedure. Refer to Body Control Module (BCM) Programming/RPO Configuration for more information.

Is the repair complete?

--

Go to Step 16

--

11

Replace the FOG LP relay.

Is the repair complete?

--

Go to Step 16

--

12

Replace the fog lamp switch. Refer to Fog Lamp Switch Replacement in Lighting Systems for service procedure.

Is the repair complete?

--

Go to Step 16

--

13

Repair a short to B+ in circuit 1317.

Is the repair complete?

--

Go to Step 16

--

14

Replace the underhood accessory wiring junction block. Refer to Accessory Wiring Junction Block Replacement in Body Front End for service procedure.

Is the repair complete?

--

Go to Step 16

--

15

The malfunction is not present at this time. Refer to Diagnostic Aids for additional information regarding this DTC.

Is the repair complete?

--

Go to Step 16

--

16
  1. Turn the ignition switch off.
  2. Reinstall connectors/components removed.
  3. Turn the ignition switch on.
  4. Clear BCM DTCs. Refer to Clearing DTCs for more information.
  5. Check for BCM DTCs. Refer to Diagnostic Trouble Code (DTC) Displaying for more information.

Are there any BCM current DTCs set?

--

Go to Diagnostic System Check - Body Control System

System OK